276 



INDEX 



Phosphoric acid of commercial 



fertilizers 211 



acid in soils 174 



acid, deficiency of 220 



acid removed in crops 173 



Phosphorus compounds of soils- .64 



Physical property of soils 10, 47 



modified by farming lor 



Plant food, classes of 69, 70 



ash and fertilizers 226 



Plowing, depth of 37 



fall 35 



spring 36 



influences nitrification- . . 127 



Potash fertilizers 186 



fertilizers, use of 194 



of commercial fertilizers- 212 



in soils 188 



in soils, sources of 188 



removed in crops 187 



and lime, joint use of 194 



Potassium compounds of soil ... 67 



Potato, fertilizers for 224 



food requirements of 233 



soils 19 



Questions 265 



Rainfall and crop production ... 25 



Rape, food requirements of 235 



References 255, 257 



Reverted phosphoric acid 1 76 



Roberts 37, 157 



Rocks, composition of 55, 59 



Rock disintegration 49 



Rolling 34 



Roots, action on soil 228 



Rotation of crops 238, 254 



of crops, principles in- 

 volved 239 



length of 244 



problems 248 



and farm labor 243 



and humus 241 



and insects 244 



and soil nitrogen 241 



Rotation and soil water 242 



and weeds 244 



Salt as a fertilizer 202 



Sand, grades of 13,14 



Seaweeds as fertilizers 203 



Sedentary soils 54 



Seed residues 132 



Sheep manure 153 



Silicon and silicates 163 



Silt particles 14 



Size of soil particles 12 



Skeleton of soils 12 



Small manure piles 165 



Sodium compounds of soil 68 



Soil, composition of 83, 85 



exhaustion 238 



types 19 



Soot 203 



Specific gravity of soil 12 



Spring plowing 36 



Stockbridge 12, 25 



Stock farming and fertility 254 



Storer 63, 1 29 



Stutzer 133 



Sub-soiling 35 



Sugar beets, fertilizers for 234 



beet soils 21 



beets and farm manures. .167 



Sulphate of potash 190 



Sulphur compounds of soil 64 



Superphosphates 178 



Tankage 130 



Taste of soils 46 



Temperature of soils 42 



Tests with fertilizers 218 



Thaer, work of 3 



Tobacco, manuring of 167 



Tobacco stems 193 



Transported soils 54 



Truck farming and fertilizers ..221 

 Turnips, fertilizers for 224 



Ville 107 



Volcanic soils 55 



